Electric piano



F933. 15, 1845. w a LA cmco JR 2,311,399

ELECTRIC PIANO Filed Nov. 30, 1940 2 Sheets-Sheet 1 Feb. 16, 1943. w. B. LA CHICOTTE, JR 2,311,399

I ELECTRIC PIANO Filed Nov. 50, 1940 2 Sheets-Sheet 2 MPL/F/f Z I Inventor (Itforneg Patented Feb. 16, 1943 UNITED STATES PATENT OFFICE ELECTRIC PIANO Walter B. La Chicotte, Jr., Haddon Heights, N. J assignor to Radio Corporation of America, a corporation of Delaware Application November 30, 1940, Serial No. 367,873

2 Claims.

invention is not limited to such devices, but that it may be applied to any equivalent type of electrical musical instrument such as electric organs or other apparatuses in which the tones are me-' chanically or electrically generated.

In some electric pianos heretofore proposed, the loudspeaker has been directed toward the floor but such an arrangement, of course, produces a great absorption of high frequency and does not produce the impression of the sound coming from different parts of the piano as is normally the case. In a different type of electric piano which has been used commercially the sound is emitted through louvres in the front of the case producing a much more natural effect when the audience is facing the piano from the front or keyboard side. However, due to the fact that such pianos have no sounding board and the back thereof is enclosed by the loudspeaker labyrinth, no sound is directed out of the back and when such pianos are used, for example, on a stage with the back of the piano facing the audience, the effect should be improved by the provision of additional loudspeakers likewise facing the audience.

In the piano of the present invention the deficiencies of the prior art constructions are avoided and. a loudspeaker arrangement is provided in which the various sounds of either high or low frequency maybe directed at will either out of the back or out of the front of the piano. is accomplished by providing a number of loudspeakers or loudspeaker passages which may be connected to the amplifier either selectivelyor collectively and these loudspeakers or loudspeaker passages may control either the high frequencies or the low frequencies, or both.

One object of the invention is to provide an electrical musical instrument in which the high frequency sounds may be directed toward the audience.

Another object of the invention is to provide an electrical musical instrument from which the sounds may be directed in any chosen direction.

Another object of the invention is to provide 5 tone."

an instrument of the class described in which a plurality of high frequency sound reproducers disperse the sound in all directions.

Another object of the invention is to provide an apparatus of the class described in which a cross-over network separates the high frequency and low frequency sounds.

Another object of the invention is to provide an apparatu of the-g class described in which sounds from a singl'loudspeaker may be selectively directed in either of a plurality of directions.

Other and incidental objects of the invention I will be apparent to those skilled in the art from a reading of the following specification and an inspection. of the accompanying drawings in which:

Figure 1 is a front view of a piano constructed in accordance with my invention,

Figure 2 is a horizontal section through the high frequency speaker units ll, 15 of Fig. l,

'g ure 3 is a schematic diagram of the speaker connections used in the apparatus of Figs. 1 and 2,

Figure 4 is a vertical section through a modifiediorm a the invention,

Figure 5 is a longitudinal horizontal section through the middle of Fig. 4 on the line 5-5,

Figure 6 is a plan view of a second modification of the invention, and

Figure '7 is a front" view partly in section of theform of the invention shown in Fig. 6.

In Fig. l the invention is shown as applied to ,.a commercial type of piano known as the Story- In this piano as ordinarily constructed, the speaker is arranged somewhat as shown in Figs. 6 and 7 and the bass notes are transmitted through a speaker labyrinth at the back of the piano, the bass notes being emitted primarliy through the louvre ll and the treble notes being emitted primarily through the louvre l2. In the present commercial construction of this device, the front of the cone 22 shown in Fig. 6 emits the high frequencies. In the construction shown in Fig. 1, the high frequencies are emitted through banks of small speaker horn units indicated at l3, l4, l5 and I6 and the high frequency sounds are delivered thereto by high speaker units II, l8, l9 and 20, respectively. These speaker units may be of the type designed to reproduce only the higher frequencies at appreciable amplitude and generally referred to in the art as tweeters. These high frequency speakers are equipped with appropriate switches so that any one or more may be turned on as desired. For example, if the pianist is performing with his back to the audience only the speaker I3 may be used while if the back of the piano is toward the audience only the speaker IE or l4, l5 and Hi my be used according to the area the sound is intended to cover.

In this form of the invention the circuit arrangement shown in 'Fig. 3 may be used. In

- this arrangement the output from the power amplifier 2| is fed through a cross-over network including the inductances .24 and 26 and the capacitors 25 and 21 which transmit the low frequencies to the speaker 22 which cause them to be emitted through the louvres H and I2 and the high frequencies are transmitted through the transformer 23 to the speaker units l1, l8, l9 and 20. The cross-over network is of more or less a usual type, the high frequencies being transmitted through the capacitors 25 and 21 to the transformer 23, while the low frequencies are transmitted through the inductors 24 and 26 to the speaker 22. Instead of feeding the speakers directly from the cross-over or frequency-selecting network, the output from-a voltage amplifier may be fed into the network, and the output therefrom may be fed to two separate power amplifiers which operate the respective speakers.

The transformer 23 is preferably provided with separate secondaries for each of the high frequency speaker units H to 20 in order ,that the impedances may be readily balanced but ,any equivalent circuit arrangement may be used. Each of the speaker units is provided with a separate switch 6, I, 8 and 9 so that the high frequency sounds, may be directed in any chosen direction. The low frequency sounds which are not so directional may be emitted through the louvres H and [2 as usual or the direction of the emission may be controlled/if desired as described hereinafter.

In the form of the invention shown in Figs. 4 and 5, the low frequency sounds from the speaker ,quency sounds may be provided by the high fremade solidly of wood or may be made of sound absorbing composition either solid or composed of a series of layers of sound absorbing and sound impeding material.

In the form of the inventio shown in Figs. 6 and 7 the loudspeaker laby intlf-is shown in much its present commerci form, but it is provided with a louvre 43 at t' e back and an opening 42 at the ,front into e body of the piano. If the valve 41 is in the sition shown, the low frequency sounds will e directed through the body of the piano and out through the louvres H and 12 as usual. In this case the high frepulled up over the opening to the front of the I may be connected if desired through the lever 44 22 are directed through a pair of labyrinths formed in the labyrinth chamber by appropriate bafiles 30 and 3|. After passing through these labyrinths or horns which are designed in the usual manner, the sounds are emitted through the closable shutters 32 or 33 which open into opposite faces of the labyrinth chamber. If the bottom of Fig. 5 be taken as representing the frontlof the piano then the closing of the shutters 33 and opening of the shutters 32 will direct the low frequency notes out the back of the piano while the closing of the shutters 32 and the opening of the shutters 33 will .direct the low frequency sounds out the front of the piano.

"Ihese shutters may be constructed in any desired and the cord 45 passing over the pulley 46 or these two elements may be independently operated. In this arrangement, as in those above described, the separate high frequency speakers may be used as shown in Figs; 1 to 3 and the high frequency side ofthe cone may remain covered. I claim as my invention: 1. man electric piano, an amplifier, a plurality of high frequency speaker units oriented in different directions and adapted to be selectively electrically connected to said amplifier, a low frequency speaker permanently connected to said amplifier, progressively enlarged sound directing means having an outlet for directing sound therefrom, mechanical means at the outlet of the sound directing means for selectively directing said sound in different directions corresponding to the directions in which it is directed by the high frequency speaker units in operation, and a casing housing all of the aforesaid elements.

2. In an electric piano, an amplifier, a plurality of high frequency speaker units oriented in different directions and adapted to be selectively electrically connected to said amplifier, 2. low frequency speaker permanently connected to said amplifier, progressively enlarged sound directing means having an outlet for directing sound therefrom, mechanical means at the outlet of the sound directing means for selectively directing said sound in the same direction as it is directed by the high frequency unit in'operation,

and a casing housing all of the aforesaid ele- 7 

